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Volcanic hazards:Assessment and monitoring

Christoph Breitkreuz,

TU Bergakademie Freiberg

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Volcanic Hazard – what can be done?

1. Hazard assessment

• Mapping of the volcano and of its products: typical eruption types

• Dating the eruptions: What is the eruption frequency? What are the

periods of dormance?

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Result: Report with hazard map as data base for decision makers during an eruption

Volcanic Hazard – what can be done?

1. Hazard assessment

• Mapping of the volcano and of its products: typical eruption types

• Dating the eruptions: What is the eruption frequency? What are the

periods of dormance?

• Weather conditions and wind directions, depending on seasons and

atmospheric level

• Volcanoes near or at the coast: Tsunami hazards

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Lahar hazard: Mt. Rainier

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2. Monitoring

Initiation of Activity („Volcano awakes“)Monitoring the seismisity (tectonic quakes vs. harmonictremors)Geodesy: change in topography, inflation of volcanic edificeMeasuring the gas composition and flux

Establishing a multi-step alert- and evacuation plan: highest alert level: Eruption within 338 hours (successful at Pinatubo 1991

Monitoring during the ongoing eruptionForecasting the end of eruption > step-wise lowering of alert levels

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Pinatubo 1991:Hazard map*, Seismic Activity*,Satellite monitoirng of atmospheric SO2

*EOS 1991

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Volcanic Ash Advisory Centers: http://www.ssd.noaa.gov/VAAC/

Airplane engine after transit through an ash cloud

Aviation hazard:Monitoring by satellites

Tagesspiegel

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Etna

EOS 75-12 (1994)

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Monitoring vertical movement withInterferometry

Wicks et al. 2002, GRL

Three Sisters, Cascades

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Hawaii Archipel

Hazard of sector collapse-induced tsunamis

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La Palma and her sisters: Tsunami hazard for the Atlantic Ocean

125-136 ka

800-1000 ka

> 900 ka

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Canary Islands: More than 14 large land slides in < 1 Ma (Masson et al. 2002)

Causes:- Volcanic eruption/

magma ascent- Earthquakes- Instability of volcanic edifice

- due to magma intrusion- due to hydrothermal

alteration

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Orsi et al. 2004

Phlegrean Fields west of Naples: Europe most dangerous volcanic region

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Campanian Ignimbrite (37 ka): Sorrent on the southern side of the Bay of Naples